- quote - Gagoze
Gagoze is a horrible-looking ghost who haunts the ancient temple Gango-ji in Nara prefecture. His story dates back to the Asuka period (550-710 CE). He is first depicted in illustration in Toriyama Sekien’s Gazu Hyakki Yakko, and he is said to take the appearance of a demon in monk’s garb.
His story says
that during the time of Emperor Bidatsu, in old Owari province (now Nagoya in Aichi prefecture), lightning struck the ground near an farmer’s house. From the lightning emerged a thunder god in the form of a young boy, and the farmer ran outside with a stick to kill the boy. The boy pleaded with the farmer to spare his life, and promised that he would return the deed by giving the farmer and his family a young boy as strong as the thunder god. The farmer agreed, and allowed the thunder god to return to the sky.
Sure enough,
the farmer’s wife soon bore a child, and the child was as strong as a thunder god! However, the child was born with a snake wrapped around his head, with the head and tail going down the back like a ponytail. When the boy turned 10, he had grown so strong and proud that he challenged a member of the imperial family to a contest of strength and won.
After this,
the boy was apprenticed to Gango-ji temple. Shortly after that, the belltower boys began dying very strange deaths one-by-one, and rumors began to spread that an oni, or demon, was behind the deaths. The boy wanted to solve the mystery, so he said he would catch the oni. He waited all night by the belltower, and towards dawn finally the oni came. The boy grabbed the oni by the hair and dragged him around so hard that he ripped his entire scalp off, and the oni was able to escape. The boy followed the blood trail left by the oni all the way to its end, where he found the grave of a (former) very lazy and bad temple servant. The lazy servant’s ghost had become this terrible ghost-demon, and the boy had defeated it! The boy became famous and grew up to be a priest at the temple, and the oni’s scalp became one of the holy treasures of Gango-ji.
The story doesn’t really tell too much about the yokai itself, but it does at least explain who Gagoze was: a lazy priest-servant-turned-demon-ghost who liked to kill children! ... - source : Matthew Meyer -

At the home of the 柿阪秀元氏 Kakisaka Hidemoto family, on the eve of the Setsubun ritual in spring, they place ritual water at the entrance and prepare a special seat for the Oni to take a rest.
They do not pierce the head of a sardine (a custom to drive away the Oni), and they call"Fuku wa Uchi, Oni wa Uchi" May good luck come in, may the Demon come in!
The family is said to have Zenki and Goki as their ancestors.

oni no shison 鬼の子孫 / onisuji 鬼筋 descendants of the Oni
Near the temple 安生寺 Ansho-Ji there are five families, who do NOT prepare chimaki 粽 ritual rice dumplings for the Boy's festival on May 5th and hishimochi 菱餅 red and white dumplings for the Girls's festival on May 3.
These families claim to be descendants of the Demons (Zenki and Goki). The Chimaki look like the tsuno 角 horns of an Oni and the Hishimochi look like oni no shita 鬼の舌 the tongue of an Oni, thus they feel it an insult against the ancestors to prepare them.
During the Setsubun rituals, they never chantoni wa soto 鬼は外 but only fuku wa uchi 福は内.

Many demons that are driven out at Setsubun come here for a rest. They are welcomed and some have a change of heart and become benevolent Oni afterwards.
The rituals on February 3 are calledonibi no saiten 鬼火の祭典 Onibi Festival

For Setsubun, farmers put together a bunch of Susuki grass with leaves of メッツタ Metta and ホーベーの葉 Hoobee to ward off the Demons.
At home they use the normal chant for Setsubun 「福は内、福は内、鬼は外、鬼は外」.
On their fishing boats they chant: 「ふか外、ふか外、鬼は内、鬼は内」- Oni wa uchi!
Good Luck get out, Demons come in!

Once upon a time an Oni appeared at the home of the 富永家 Tominaga family and since that time, the family was blessed with good fortune.
Since then, they throw beans and chant at Setsubun福は外鬼は内 Fuku wa soto, Oni wa uchi!
Once there was a fire in the castle town of Kanazawa. A black cloud in the form of an Oni appeared over their house and spread like an umbrella, protecting it from burning down.